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Author Topic:   step headers or not??
66jj
Member
posted July 28, 2003 05:40 PM
Im wondering on a imca stock car would step headers be the way to go??


350 cfm carb.


Big Bear
Member
posted July 28, 2003 06:44 PM
There's an article in the Jan 2002 Circle track titled "Exhaustive Choices" Just got done reading it myself and there seems to be some advantages in the ability to move your torque curve around. Check it out

Big Bear

outlawstock17
Member
posted July 28, 2003 06:52 PM
this is my first season with step headers and i like them. i use a howe crossover header with 1 3/4" primary going into 1 7/8" and then into a 3 1/2" collector, an "X" pipe and a 2 schoenfeld 3 1/2" mufflers. best sounding, best performing exhaust system i've had to date. this is on a practically unlimited engine though.


istock59
Member
posted July 28, 2003 09:23 PM
Hey 66jj, I just switched from a set of Dynatech 1-5/8" straight tube headers, to a set of Schoenfeld 1-1/2":1-5/8" step headers. Sure changed the tone of the exhaust, and in my opinion, it makes more power too.

This is on an IMCA Stock too, with the dinky 350 carb...

66jj
Member
posted July 28, 2003 09:42 PM
I have been using stepped headers for 7 years, but my theory was for bottom end, pulling of the corners. I was running pavement sportsman type.

I also allways have used 2.5 inch pipes and loback lw mufflers. My car has allways been the quitest, but Ive never lacked pull of the corner with claimer type motors.

I stock 59, have you thought of adding mufflers?? I think I stocks are dumping torque right out the pipes. From what Ive read over and over, some backpressure, and pre cylinder heat is a good thing for torque.

I may get laughed at but Ill have the same system Ive allways used.

What carb are you running, is a Dorton really worth all that??

Ill be racing in Anderson,Nichols,Blessingtons back yards.lol.

thanks jeff

istock59
Member
posted July 29, 2003 07:11 PM
I haven't heard of anybody running mufflers 66jj, but a little backpressure could be a good thing. I believe that's the theory behind the 1.5" tube headers I'm using. I played with some header collector extensions for a while last year, but never really noticed a difference. I'd run them this year, but the x-brace is in the way on this new car.

FWIW, I run the standard 7448, not the Dorton. But it's been reworked by Kinetic Performance (kplugnut here on the forum). I've borrowed a Dorton before and couldn't tell the diff.

[This message has been edited by istock59 (edited July 29, 2003).]

66jj
Member
posted July 31, 2003 09:20 PM
ok i talked to several engine builders who own dynos, all of them said step headers are not showing any difference below 7000 rpm.

also I was told that the longer collector,reducer I can use the better, and some backpressure, is better than just running straight pipes.

they all suggested at least a reduction in pipe size for backpressure, or even mufflers like schoenfields.

istock59
Member
posted July 31, 2003 09:45 PM
Did you ask them about header tube size with the 350 cfm carb? I think it was one of the Hendrens (Bill or Steve) that recommended the 1.5" tube on another forum.

FWIW, when I bought my Schoenfelds, it wasn't the step I was really after, but the small tube.

Also, how long of a collector/reducer were they recommending?

66jj
Member
posted August 01, 2003 05:12 PM
OK, I told them my common rpm would be 6200 max.. maybe up to 6500 once in a while.

I was told go with 1.75 and reducers of at least 12 inches, which I have never seen. I have used the flowmaster reducers in the past which are tapered and about 8-10 inches I think. they are saying to go from 3.5 collector to 2.5 pipe which is what I have allways done.

I was also told that merge collectors would be a huge improvement. I know howe sells some stainless steel ones for 300 each.lol.
I bet if you put some merge collectors on and won a lot Imca would make them illegal anyways.

On a side note Steve on here also said to me in a pm before that with the 500 carb they were making more power with 230 heads than 200 or 215, which I would not have guessed. I was hoping to use some 305 heads and ft pistons. He also said as much compression as possible.

I think I was more on your thinking 59, small stuff to all match the carb and make torque. I guess not.

What are you running for a motor,everyone is running 406 motors here with darts or vortecs. period, I havent seen a set of double humps yet in the pits.

I have one ft 406, and parts for 2 383s.

CLBaker25
Member
posted August 02, 2003 06:34 AM
Baker, do you race at Beatrice??

I wonder if Demon will get their 350 cfm carb imca approved.

I ran a demon 750 and it was way better than a holley, gained 2-300 rpm instantly. It compares more to a holley HP.

Is the carb speedway sells as the dorton the same as everyone is running?

Jeff

CLBaker25
Member
posted August 02, 2003 12:00 PM
Jeff,

I help Michael Sherwood on his car. He drives the #33 at Beatrice in the stock car class. I am unfortunately in Bosnia thru the end of the racing season. I might be back for Octoberfest but we will see. I am not sure about the comparison with the speedway carb. We bought a carb from a guy used. But it is a dorton.

Baker




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